The present patent application claims the benefit of earlier Japanese Patent Application No. H11-269837 filed on Sep. 24, 1999, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
This invention relates to an improved arrangement of a hose clamp for attaching a rubber hose to the end of a connection pipe, which does not require a separate holder to keep the hose clamp at a loosened position.
2. Description of the Related Art
A hose clamp is used to attach a rubber hose to a pipe. In general, hose clamp has a clamping position for tightening the hose against the outer wall of the pipe, and a loosened position for allowing the end of the pipe to be 20 inserted into the hose. A holderless-type hose clamp, which does not require a separate holder for retaining the clamp at a loosened position, has been proposed in, for example, Japanese Patent Application Laid-open No. 10-61855.
FIGS. 1a and 1b illustrates an example of such a prior art holderless-type hose clamp. The hose clamp 1 is comprised of a clamp ring 2 made of a strip of spring leaf rolled into a loop with the ends overlapping each other. First and second pinches 6 and 9 extend from the ends of the clamp ring 2, and are projected up in the radial direction of the clamp ring 2. The first pinch 6 includes a frame having the same width as the clamp ring 2, combined with an opening. The opening is connected with a guide groove formed in the clamp ring 2. The frame has a projection 7 extending in the radial direction. A stopper 11 extends from the frame toward the inside opening with its end 12 bent zigzagly down. The width of the second pinch 9 is narrower than that of the first pinch 6, and is movable in the guide groove. The second pinch 9 has a tooth 14 and a shifting edge 9a that can be displaced by the axial movement of the second pinch 9 under an external force.
In the natural state, the clamp ring 2 is at a clamping position by its own restoring force. To loosen the clamp ring 2 in order to receive a pipe, a pair of pliers is used to bring the pinches 6 and 9 closer to each other along the circumference of the clamp ring 2. The tooth 14 of the second pinch 9 gets behind the stopper 11 of the first pinch 9, and then, it is meshed with the stopper 11. In this state, the clamp ring 2 is held at a loosened position, and a pipe is inserted in the hose.
To release the engagement between the tooth 14 and the stopper 11, the shifting edge 9a of the second pinch 9 is displaced by pliers in the radial direction, thereby being moved away from the stopper 11. The displacement of the shifting piece 9a causes the tooth 14 to be disengaged from the stopper 11. Consequently, the clamp ring 2 restores to the clamping position having its own restoring force, and tightens the hose against the pipe.
This type of conventional hose clamp does not require a separate holder to retain the pinches at a closer position to keep the clamp ring 2 loose.
However, the conventional hose clamp illustrated in FIGS. 1a and 1b has problems in size and reliable disengagement of the tooth 14 from the stopper 11. In releasing the engagement, the edge of the projection 11 of the first pinch 6 and the shifting edge 9a of the second pinch 9 are held by a pair of pliers, and moved in the axial direction of the clamp ring 2. For this reason, the projection 7 of the first pinch 6 and the shifting edge 9a of the second pinch 9 must have a sufficient size to allow the pliers to grasp the edge of projection 7 and the shifting edge 9a. This means that the pinches 6 and 9 can not be made smaller in the radial direction.
If the pinches 6 and 9 are made too small, then they can not be held by the pliers because the projection 7 and the shifting edge 9a, both extending in the radial direction of the clamp ring 2, become insufficient.
The stopper 11, which extends into the opening, also disturb the pliers from reliably grasping the shifting edge 9a. In addition, since the shifting edge 9a is entirely positioned within the width of the frame of the first pinch 6, the pliers are very likely to slip from the shifting edge 9a. 
The present invention was conceived to overcome these problems in the conventional hose clamp, and it is an object of the invention to provide an improved holderless-type hose clamp.
To achieve the object, a hose clamp of the present invention includes a clamp ring made of a metal strip rolled into a loop with its ends overlapping each other. The clamp ring has a restoring force. First and second pinches are projected up from the ends of the metal strip in the radial direction. The first pinch has a frame that defines an opening inside it, and a stopper wall swelling into the inside opening from a corner of the frame. The second pinch gets through the opening of the first pinch, so that the first and second pinches cross each other. The second pinch has an operation chip extending in the width direction of the clamp ring. A stopper rises from the clamp ring near the root of the second pinch.
The hose clamp has a clamping position, at which the first and second pinches are apart from each other, and a loosened position, at which the first and second pinches are very close to each other. At the loosened position, the operation chip of the second pinch sticks out from the clamp ring in the width direction of the clamp ring.
When the hose clamp is brought into the loosened position, the stopper gets out of the opening of the first pinch, and abuts against the rear face of the stopper wall at the loosened position, whereby the clamp ring can be kept at the loosened position.
Preferably, the stopper wall has a hook, which prevents the stopper from slipping off from the stopper wall at the loosened position. Preferably, the hook is made monolithically with the stopper wall.
These arrangements allow the hose clamp to be made compact, while allowing the users to easily and reliably loose and tighten the hose clamp. In addition, the hose clamp can be kept at the loosened position in a safe manner.